To enlarge the tcp window size of NT4, have a look at :
http://premium.microsoft.com/msdn/library/winresource/dnwinnt/f1d/d1e/s8516.htm
If you change :
TcpWindowSize (Dword) to 65535
EnablePMTUDiscovery (Dword) to 1
EnablePMTUBHDetect (Dword) to 1
you will have a tcp window size of 64Ko.
A+.
Christophe.
Jack Stiekema wrote:
> > -----Original Message-----
> > From: Tom Saam [mailto:[email protected]]
> > Sent: Monday, August 10, 1998 1:15 PM
> > To: Jack Stiekema
> > Subject: RE: windows 95 and NT
> >
> >
> > Jack-
> >
> > Two things:
> >
> > 1) TCP Slow Start (windowing) hurts small file sizes or
> > links with any kind of error rate.
>
> Thanks Tom,
>
> Tracing gives a nice 1, 2 ,3 4, 5, 6 packets, and then it't stable 6 (5x1500
> and 1x932)so i guess the NT does not like to increase it's default window
> size despite of all the papers who say it should.
> I also had the suggestion that maybe the NT just does not have enough send
> buffers
>
> I have a Philips collegue visiting Microsoft in the US this moment, i just
> mailed him my questions let's hope he get's the answers.
> The question he will ask Microsoft:
> "
> Server is NT4 (build 1381,sp3, winsock2 entry in registry),
> client is NT4 (build 1381,sp1, winsock2 entry in registry),
> in between i have a 200ms WAN/satellite simulator.
> So the total RTT is 400ms on a 10mb ethernet link.
> I made on both NT's the the MTU 1500, the TcpWindowSize 14800, enabled MTU
> detect and disabled black hole detect but:
>
> If i make a ethernet trace (of a ftp session, and of a tcp test tool) i see
> that there are 5 packets of 1500 and 1 of 932 bytes, this equals 8432 the
> default window size of Microsoft.
> As there is only 8kb every 400mS the total transfer rate is 22kB a second,
> and not the 10meg we were hoping.
>
> Whatever i do (use a win95 winsock2 client, put windowsize in all
> device/parameter/tcp registry entries) i can not get the window size larger
> then 8k.
> I need to enlarge the RWIN to 1meg in order have decent transfer rates at
> satellite links
>
> So the questions is:
> How tho enlarge the TcpWindowSize to 1 meg on win95 and NT4?
> "
>
> Jack Stiekema
>
> Cap Gemini Nederland bv
> Industry, Product RElated Software Solutions
> Phone: +31 6 22240066
> Fax: +31 598 398008
>
> >
> > 2) TCP typically generates 2 acks for every MTU, so the
> > dial return
> >
> > ack rate can be a bottle neck.
> The second one should be ignored by the receiver, so it should not hurt.
>
> >
> > ....just some ideas!
> Thanks for the help Tom and all the others.
>
> ------------------------------------------------------------------------
>
> Jack Stiekema <[email protected]>
>
> Jack Stiekema
> <[email protected]>
> Work Voice: 030 252 9219
> Home Voice: 0598 380498
> Voice Cellular: 06 22240066
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> Additional Information:
> Version 2.1
> Last Name Stiekema
> First NameJack
> Revision 19980629T081522Z
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